Tool-System-Guide.md

sidebar_position	4
title	Tool System Guide
description	Complete guide to the DelReact tool system

User Guide

A simple and powerful tool system that enables automatic tool injection, custom tool registration, and seamless integration with the DelReact agent framework.

🎯 Overview

The Tool System provides:

• Automatic Tool Injection: Tools are automatically available to agents via the Tool Registry
• Custom Tool Registration: Developers can easily add their own tools
• Cross-Agent Tool Sharing: Tools registered once are available to all agents
• Memory Integration Ready: Foundation for future memory-aware tool execution

🏗️ Architecture

┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐
│   Tool Registry │◄───┤   BaseAgent      │◄───┤  Custom Agent   │
│   (Singleton)   │    │   (Enhanced)     │    │  (Your Code)    │
└─────────────────┘    └──────────────────┘    └─────────────────┘
         │                       │                       │
         ▼                       ▼                       ▼
┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐
│ Default Tools   │    │   LLM Call       │    │ Agent-Specific  │
│ - Web Search    │    │ (Tool Injection) │    │ Tools           │
│ - Fetch Page    │    │                  │    │                 │
│ - Enhance Prompt│    │                  │    │                 │
└─────────────────┘    └──────────────────┘    └─────────────────┘

🚀 Quick Start

1. Using Default Tools (No Setup Required)

import { ReactAgentBuilder } from "delreact-agent";

const agent = new ReactAgentBuilder({
  geminiKey: "your-gemini-key"
});

// Default tools (web-search, fetch-page-to-markdown, enhance-prompt) 
// are automatically available
const result = await agent.invoke({
  objective: "Search for current TypeScript best practices and summarize them"
});

DelReact Tool System Guide

This guide explains how to create, register, and use custom tools in the DelReact agent framework using the createAgentTool abstraction and the ReactAgentBuilder.

---

1. Generate Tools with createAgentTool

Define a tool with a simple, type-safe schema and business logic only:

import { createAgentTool } from "delreact-agent";

const breakEvenCalculatorTool = createAgentTool({
  name: "break-even-calculator",
  description: "Calculate the break-even point (units and revenue) for a business.",
  schema: {
    fixedCosts: { type: "number", description: "Total fixed costs in dollars" },
    variableCostPerUnit: { type: "number", description: "Variable cost per unit in dollars" },
    sellingPricePerUnit: { type: "number", description: "Selling price per unit in dollars" },
    agentConfig: { type: "object", description: "Agent configuration (optional)", optional: true }
  },
  async run({ fixedCosts, variableCostPerUnit, sellingPricePerUnit }) {
    const bepUnits = fixedCosts / (sellingPricePerUnit - variableCostPerUnit);
    return { breakEvenUnits: Math.ceil(bepUnits) };
  }
});

• No need to import or use zod or tool directly.
• For advanced validation, you can pass a zodSchema instead of schema.

---

2. Add Tools to Agent Builder

Register your tools with the agent builder using .addTool():

import { ReactAgentBuilder } from "delreact-agent";

const agentBuilder = new ReactAgentBuilder({
  openaiKey: "sk-...",
  geminiKey: "...",
  sessionId: "my-session"
})
.addTool([
  breakEvenCalculatorTool,
  // ...other tools
]);

• You can add multiple tools at once as an array.
• Tools are registered globally for the agent instance.

---

3. Build, Init, and Invoke the Agent

Build and Initialize

const agent = agentBuilder.init({
  selectedProvider: "openai",
  model: "gpt-4.1-mini"
}).build();

Invoke the Agent

const result = await agent.invoke({
  objective: "Analyze break-even for a SaaS business",
  outputInstruction: "Summarize the financial position."
});

console.log(result.conclusion);

• The invoke method runs the full agent workflow with your tools.
• The result includes the agent's conclusion and full state.

---

4. Quick Reference

Step	Code Example (TypeScript)
Create Tool	const myTool = createAgentTool({ ... });
Add Tool(s)	agentBuilder.addTool([myTool, ...]);
Build & Init	const agent = agentBuilder.init({ ... }).build();
Invoke Agent	const result = await agent.invoke({ objective, outputInstruction });

---

5. Advanced: Custom Zod Schema

import z from "zod";

const advancedTool = createAgentTool({
  name: "advanced-tool",
  description: "Tool with advanced validation.",
  zodSchema: z.object({
    foo: z.string().min(3),
    bar: z.union([z.number(), z.string()]),
    baz: z.array(z.boolean())
  }),
  async run({ foo, bar, baz }) {
    // ...
  }
});

---

For more, see the full examples in the /examples folder. Start using tools today with minimal setup, and extend the system as your needs grow!